Good Afternoon,
I am making some window/flower boxes. They are made of cedar and will be primed and painted with some clear coats. Due to the constant exposure to wet soil my concern is the box interiors.
Unfortunately, I could not find a plastic insert that would fit the demensions requested. My plan has been to caulk and paint the interiors the same as the exteriors. Now I’m questioning if that will be sufficient protection and/or perhaps harmful to the plants.
Is there a consensus re window/plant box interior finishing?
Should I fabricate plastic inserts?
Thanks, TWG.
Replies
I'm a bit confused--you speak of priming and painting, and then of clear coats. What kind of look are you after? What products were you thinking of using? In what environment will the boxes live, in particular how much sun do will they get? How do you plan for drainage from the boxes?
Hey Steve,
I am going to prime, paint (hunter green) and then spray on some clear coats for extra protection. The primer is Kilz2 and the paint will be an oil based enamel (probably Sherman Williams). I have not selected a clear spray yet.
I have to presume they will be in direct sunlight and probably not taken in during the PA winters. Drainage will be accomplished via holes drilled into the bottoms.
The clear coat is likely to be the weak link, though better over paint than over wood. If you have about $70 a quart there are some marine clear coats that would hold up, but not over "paint" (the solvents in the clear coats would eat the paint) it would have to go over two part marine urethanes. Interlux "Perfection" is one I have used. Follow the instructions to the letter.
Now, after the flight of fantasy, I would just upgrade the paint to a marine enamel and skip the clear coat. If you must for appearance, clear coat with a good marine grade spar varnish. Epifanes Gloss, Interlux Schooner, or Pettitt Captain's. These will amber the green a bit, so check out the total effect before nailing down the green color.
For extra durability inside the box, you might begin with waterproofing with a low viscosity epoxy--Smith and Co. makes a good one--instead of using the primer. The epoxy is designed that when overcoated inside a specific time window there is a crosslinking between the epoxy and the paint that adds to adhesion. Again another place to read and follow the instructions carefully.
twg
I have made many planter boxes over the years for commercial customers (restaurants, hotels and so on), and the one constant, as requested by architects and interior designers, has been galvanized sheet metal liners, with welded seams. The trick is to keep the wood dry. Finish of the wood is therefore less of an issue and can be decided purely on the basis of aesthetics.
You mentioned plastic liners...just as good if they fit well.
Steve brings up an important question, and that is drainage. If drainage is not possible, then you need to put a generous gravel base mixed with and covered in charcoal and followed by the planting medium. Avoid soil and use synthetic medium because it is lighter and breaths more easily. Your excess water will collect in the gravel layer, however, you will need to control the amount you water, because your drainage is limited this way, and you need to allow evaporation to do its job. JL
jeanlou, I believe your right that these boxes should be lined. Either galvanized, copper or some type of exterior plastic.
Steve, If I use a gloss marine enamel perhaps I won't need clear coats. I was just looking for the clears for extra protection. What do you think about the marine enamel alone?
Secondly, would the spar varnishes color as much as Waterlox sealer does (if you have ever used WL)?
Thanks for all of your help.
Clear finishes are more vulnerable to UV light than paint with pigment. The pigment blocks the lightn so that the finish doesn't deteriorate so quickly on the inside where it has the biggest impact on adhesion. Marine enamel will outlast clear coat by many times. Adding the clear coat will shorten the time before you need to refinish. So for the parts exposed to sun I'd think the paint alone would be best.
Spar varnish will color about as much as Waterlox on a comparable thickness basis. Over wood 6 coats of full strength spar varnish are recommended. This would take about 18 coats of Waterlox.
For the inside, if you cannot get a liner to fit, I think you will have to get some sort of pine tar/ pitch or asphaltum to line it, if it is to last longer than a season. For a season long, just paint it.Gretchen
Hello
My part time job is exterior trim work which involves a large amount of cedar work. I take the scrap home and make flower boxes and bird houses. I sell those to help support my furniture making habit. Here is what has worked well for me hope it helps. First you need to make sure you put some drain holes in the bottom of the boxes. 3/8 holes tend to work the best. Next have your wife place a little gravel in the bottom of the box. Caulking the joints is fine as long as you have the drain holes. Any oil based finished you have laying around will work to protect the inside. Whatever I use on the outside if I have some left I use it on the inside. Solid color stain is better than paint since it tends not to peal. Good luck
Scott
TWG one of my first projects - made them out of leftover fence slats, screwed and caulked with one coat of whatever paint was left from the outside of the house. Been used for 10 years with no protection on the inside, just full of dirt. No sign of rot. Cheap enough to replace if necessary. If doing it again, I would just use wire screen in bottom and just use the plastic pots the flowers come in.
Thanks everyone for your replies.
These are the first exterior items I've made and the customer was looking at some high-end stuff bf she asked me. Consequently, I want to build these to impress. We will see what resolution my shopping offers today
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